Chapter 2 Section 1 Streams and Rivers
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Transcript of Chapter 2 Section 1 Streams and Rivers
Chapter 2 Section 1 Streams and Rivers How Do Rivers Begin?
Rivers begin as trickles of waterthat run over the ground and join
together in larger streams. Rain that falls can Evaporate
immediately Soak into the soil as groundwater Form runoff (water
that flows over the ground surface) that can eventually lead to a
river. Rain that falls ? Time to review! Time to review! Evaporate
immediately Rain that falls
Soak into the soil as groundwater Form runoff Time to review!
Factors That Affect Runoff
The nature of the ground surface (water passes through soil easier
than cement, so grass/plants will slow water down as it is
absorbed) The rate of rainfall (a lot of rain cant all soak in, so
some becomes runoff) Whether the land is flat or hilly (water falls
faster down a steep slope than over flat ground, so the water moves
too fast to be absorbed and forms a stream instead) River Systems
The smaller streams and rivers that feed into a main river are
called tributaries. A river system is made of the main river and
all of its tributaries. Watersheds The land area that supplies
water to a river system is called a watershed or drainage basin.
The Clinton River Watershed, which ends at Lake St. Clair is the
nearest major watershed. However, the Great Lakes Watershed also
impacts us as well. * technically Grosse Pointe is considered
direct drainage which means we drain directly into Lake St. Clair
and not into a watershed Watersheds One watershed is separated by
another by a ridge of land called a divide, and streams flow in
different directions on each side. New Vocabulary Words River
Systems: Runoff Tributary River system
Watershed Divide Rivers Shape the Land Erosion is the process
during which fragments of soil and rock are broken off from the
ground surface and carried away. Rivers Shape the Land Deposition
the process during which soil and rock are left behind and build
up. How do rivers shape the land?
Rivers wear away landforms through erosion and build new landforms
through deposition. With erosion, sediment is carried away. Soil
and rock are left behind with deposition. New terms: erosion and
deposition Rivers Shape the Land Rivers wear away landforms through
erosion and build new landforms through depositions. The particles
of rock and soil that are picked up and moved by erosion and
deposition are called sediments. Rivers Shape the Land The faster
the water flows, the more energy it has to move heavier sediments.
Three factors affect a rivers speed: The steepness of the slope
(steeper = faster) The amount of water in the river (more = faster)
The shape of the channel (deeper/broader = faster) How fast is that
river? Time to Review! Factors affecting
the speed of a river ? How fast is that river? Time to Review!
Factors affecting
the speed of a river The steepness of the slope The amount of water
in the river The shape of the channel Profile of a River The many
small streams that come together at the source of the river are
called the headwaters (usually fast, choppy, and narrow). Profile
of a River Downriver, the channel becomes deeper and wider due to
erosion, it is less steep, has more water in it from tributaries,
and continues to move swiftly but much more smoothly. The Flood
Plain The broad, flat valley (created by years of erosion) through
which the river flows is called the flood plain. Profile of a River
Small obstacles in the rivers channel cause the water to flow
slightly to one side or the other, creating a bend in the river.
Profile of a River The process of eroding and depositing sediments
on the curves of a river channel will gradually form loops called
meanders. Profile of a River
https://www.youtube.com/watch?v=4qKS_Nk7UmY
The crescent-shaped, cutoff body of water that remains after a
river breaks through the ends of a meander is called an oxbow lake.
https://www.youtube.com/watch?v=4qKS_Nk7UmY Profile of a River The
mouth is the point where a river flows into another body of water
(a larger river, a lake, or an ocean). Use the diagram below to
answer #14 - #18: Profile of a River Profile of a River When the
river hits the larger body of water at the mouth, it instantly
slows down. This slow speed allows most of the rivers sedimentto be
deposited and build up at the rivers mouth, in an area called a
delta. Profile of a River New Vocabulary Words Profiles of a River
Headwaters Flood plain
Meanders Oxbow lake Mouth Delta Rivers and Floods A flood occurs
when the volume of water in a river increases so much that the
river overflows its channel. Precipitation can add more and more
water to a river, making it faster and stronger. Can Floods Be
Controlled?
A dam is a barrier across a river that may redirect the flow of the
river to other channels or store the water in an artificial lake.
Fear or welcome a flood? Yeah flood!!!
Deposition leaves a layer of nutrient rich sediment behind. Boo
flood! Destroy farms and crops Destroy homes Loss of electricity,
transportation, clean water Injury or death of people and livestock
Can Floods Be Controlled?
Levees are long ridges formed by deposits of sediments alongside a
river channel. Man-made levees are also used to make natural levees
stronger. Can Floods Be Controlled?
When Hurricane Katrina hit New Orleans, Louisiana in 2005, some of
the levees broke and flooded large areas of the city. When does a
flood occur? A flood occurs when the volume of water in a river
increases so much that the river overflows its channel.
https://www.youtube.com/watch?v=RNde3bnXaVM Fear or welcome a
flood? Yeah flood!!!
Deposition leaves a layer of nutrient rich sediment behind. Boo
flood! Destroy farms and crops Destroy homes Loss of electricity,
transportation, clean water Injury or death of people and livestock
How can we control floods?
Build a dam a barrier across a river that may redirect the flow of
a river to other channels OR store the water in an artificial lake.
Levees can be natural or people made.People can build up a natural
levee with sandbags. Vocabulary Words: dam and levee
https://www.youtube.com/watch?v=oD4QHkN57FM